Definition
The formal act of depriving a forced heir of the inheritance to which the law would otherwise entitle them. Disinherison is a concept rooted in civil law systems, where certain heirs — typically close descendants or ascendants — hold a legally protected share of the estate (the legitime or forced portion) that a testator cannot ordinarily defeat by will alone. To accomplish disinherison, the testator must act affirmatively, in proper legal form, naming the heir expressly and stating a recognized just cause. A disinherison that omits these requirements is null and of no effect.
Disinherison differs from simple omission or preterition. It is not enough for a testator to simply leave a forced heir out of the will; the heir must be explicitly disinherited, with cause stated, in order for the exclusion to stand.
Common Language
Webster's 1913: "Same as Disherison."
Wiktionary: Redirects to disherison; no independent definition given.
The common-language trail leads immediately to disherison, a variant spelling of the same concept. Neither term has meaningful currency in ordinary modern English outside legal and historical contexts. Researchers should treat disinherison and disherison as interchangeable spellings, not distinct concepts — but should be careful not to conflate either with disinheritance as used in common-law systems, where the concept operates quite differently (see COMMON CONFUSION below).
Common Confusion
Disinherison vs. Disinheritance: In common-law jurisdictions, a testator generally has near-absolute testamentary freedom and may disinherit any heir simply by omitting them or expressly excluding them from a will. No cause need be stated; no formal procedure is required. Disinherison, by contrast, operates in civil law systems where forced heirship creates a vested legal entitlement in certain heirs. The procedural and substantive requirements for disinherison — express naming, just cause, proper form — reflect this structural difference. Using disinheritance and disinherison interchangeably in civil law research will produce errors.
Disinherison vs. Preterition: Preterition is the accidental or unexplained omission of a forced heir from a will. Disinherison is deliberate and formal. The legal consequences differ: preterition may entitle the omitted heir to claim their forced share despite the will; a valid disinherison extinguishes that entitlement.
Why It Matters in Research
Researchers working in Louisiana succession law will encounter disinherison as a live legal concept, not merely a historical artifact. Louisiana's forced heirship regime, derived from French and Spanish civil law, preserved formal disinherison requirements well into the modern era, with the forced heir class and grounds for disinherison modified by constitutional amendment and statute in the late twentieth century. Sources predating those changes — particularly nineteenth and early twentieth century Louisiana cases and treatises — describe a broader forced heir class and different enumerated grounds. Do not assume continuity across that boundary without checking the applicable law for the period in question.
Outside Louisiana, disinherison appears primarily in historical sources discussing Roman law, the civil law tradition, or comparative succession. In those contexts, the term signals a civil law framework and should prompt the researcher to apply civilian analytical tools, not common-law ones.
The Rapalje & Lawrence entry cross-references disherison rather than providing its own definition, confirming that the two spellings were used without distinction even in nineteenth-century practice dictionaries. Searches in historical corpus materials should run both spellings.
Researchers using Black's (1st and 2nd editions) or Bouvier's should note that these sources describe the civil law concept accurately but briefly. Bouvier goes furthest, connecting disinherison to the Louisiana context and flagging the formal requirements. For substantive treatment, Bouvier's cross-references to FORCED HEIRS and LEGITIME are the necessary next steps within that source.
Historical Dictionary Support
Black's (1st and 2nd editions) and Bouvier's converge on a single definition: disinherison is the act of depriving a forced heir of a legally protected inheritance. The definitions are nearly identical across all three entries, which reflects the settled, narrow scope of the concept within civil law doctrine rather than any copying error.
Bouvier's is the most useful of the shelf sources for this term. It adds the Louisiana-specific procedural requirements — proper form, express naming, just cause — and flags nullity as the consequence of non-compliance. This reflects Bouvier's characteristic attention to American practice, particularly in jurisdictions with civil law heritage.
Rapalje & Lawrence provides no independent entry, redirecting to disherison. This is consistent with nineteenth-century American legal usage treating the spellings as variants.
What the historical sources collectively omit: any discussion of the enumerated grounds for just cause, the distinction between disinherison of descendants versus ascendants, or the evolution of forced heirship law over time. Researchers needing that depth must go beyond these dictionary sources to treatises on Louisiana succession or civilian inheritance law.
Jurisdictional Note
Disinherison as a formal legal concept applies primarily in Louisiana among American jurisdictions. Civil law countries (France, Spain, and their legal descendants) have analogous concepts under their own succession codes, though terminology and procedural requirements vary. In common-law states, the concept is inapplicable; testamentary freedom renders formal disinherison unnecessary.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Forced Heirs; Legitime; Succession (Civil Law); Testamentary Freedom.